ADS1282-HT: ADS1282

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Replies: 3

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Part Number: ADS1282-HT

Using a single supply of 5V, the reference should also be 5.0V with the Vref+ at 5.0 and the Vref- to gnd? Is this correct? With a differential amplifier driving Vin+ and Vin -, If this voltage went to 0 or 5V can the part tolerate this? Thanks.

3 Replies

  • Hi Knute,

    It does depend a bit on which voltage you are talking about. A 5V reference is fine with a 5V AVDD. If you use the PGA with a gain of one, then per the input range equation your full scale input range would be +/-2.5V differentially. You must also adhere to the absolute input range though, which is the maximum voltage you can put on a single pin. In this case it would be 3.75V (AVDD-1.25). You can think of this as effectively placing a limit on where you should set your common-mode. A +2.5V differential signal means one input will move +1.25V and one will move down -1.25V. Since the largest voltage you can have on the input is 3.75V, your common-mode should not be greater than 2.5V. Similar logic applies to the low end, but the input range is a little more forgiving allowing you to swing to AVSS + 0.7V. Hope that helps!

    Best,

    Zak  

    Regards,

    Zak Kaye
    Precision Amplifiers Applications 

  • In reply to Zak Kaye:

    Thanks.  If the input voltage goes overrange to 0V or 5V, the conversion will not be good but will the part be damaged?  The absolute maximum spec for the analog input voltage is VSS-0.3 to VDD+0.3, which in this case is -0.3V to 5.3V.

  • In reply to Knute Ray:

    Hi Knute,

    The part should not be damaged, but as you mention the conversion will be invalid as the PGA goes into saturation. There would be some overload recovery time associated with this as well.

    Best,

    Zak

    Regards,

    Zak Kaye
    Precision Amplifiers Applications